For new and existing Microsoft Sentinel customers, there’s a free trial available that provides data ingestion and retention for a 31-day period. It’s easy to kick off the trial. You just create a new Log Analytics workspace and enable Microsoft Sentinel on the workspace.
See Quickstart: On-board Microsoft Sentinel
But, how do you know when the trial starts and when it ends? And how can you tell if an existing workspace has already been enabled sometime in the past?
After you successfully enable the Microsoft Sentinel trial period by Sentinel-enabling a new Log Analytics Workspace, a notification will display, letting you know the clock has started.